1. Field of the Invention
The present invention relates generally to radio frequency (rf) communication systems, such as a two-way, multi-user private radio system, particularly to a communication system and method for routing signals to multiple remote devices connected to a remote receiving device.
2. Background and Objects of the Invention
In private radio systems such as conventional land mobile radio (LMR) systems, multiple radio transceivers, including for example portable radio units and mobile radio units, initiate and carry on communications over a preselected radio frequency channel, typically via a base station repeater. Land mobile radios are particularly used by police and fire departments, rescue workers, paramedics, power and telephone company field technicians, municipalities, and other mobile groups that require immediate communication with other members of their respective group. Communication between the various members can include visual information, which may be displayed on a mobile data terminal (MDT). For example, a police officer on patrol can request and receive information from a base or host computer about a stopped motorist, which is displayed on an MDT in the patrol car.
With reference now to FIG. 1 of the drawings, there is illustrated a conventional private radio communication system, generally designated with the reference numeral 10, employing a conventional protocol. In particular, a Transmitting Data Terminal (TDT) 12, e.g., an MDT, is connected to a Data Originating Mobile (DOM) radio 14, e.g., a first private radio device via a wireline communications link 16, e.g., an RS232 link. The DOM 14 includes an antenna 14A for transceiving rf messages, e.g., transmitting a data message from the TDT 12 (via link 16) over an rf channel to a base station repeater (RPT) 18, which receives and transmits the message via an antenna 18A. The forwarded data message is then sent to a Data Receiving Device 20 (DRM) through an antenna 20A and forwarded across another wireline communications link 22 to a Receiving Data Terminal (RDT) 24, e.g., another MDT.
The conventional protocol used in the aforementioned communications link between the TDT 12 and the RDT 24, discussed in more detail hereinafter, however, allows data to be transmitted to only one such RDT device 24 attached to the DRM 20, e.g., the other MDT. There is no provision in the conventional system and protocol shown in FIG. 1 for routing the data message to other attached devices, e.g., a printer (not shown) also attached to the DRM 20. Further, there is no provision for routing the data message to the DRM 20 itself, e.g., to a diagnostic or other application residing therein. Additionally, the conventional system 10 and protocol do not provide for multiple RDT 24 addressing, i.e., to applications therein.
It is, therefore, an object of the present invention to provide a private radio communication system and method for a first user to forward a data message to at least one of multiple remote devices attached to the DRM 20.
It is also an object of the present invention to provide a communication system and method for the first user to forward the data message to applications stored within remote devices such as the DRM 20 and RDT 24.